Yeah, I’m getting exactly the same error. For Scott’s edification, here’s what I’ve learned in my own troubleshooting of this plugin …
From PayPal tech support (after a 1-hour call):
1. My PayPal account is properly set up for digital media sales.
2. All my API codes are correct.
3. When testing the plugin, PayPal is getting the API calls, sending the Express Checkout token, then it breaks down for some reason.
4. Their conclusion was that it’s either my linux hosting service (GoDaddy) running the wrong version of PHP, or an issue with the plugin code in either encrypt_url.php or paypalfunctions.php.
So then I called GoDaddy tech support. They tell me my linux hosting server is running PHP v5.3. I could get up to PHP v5.5 by switching to their C-panel hosting for not much additional cost, but I’m trying here first to see if maybe Scott has made any progress on this 4-month-old topic.
Curiously, on a StackExchange discussion I found this thread that says one person resolved this error by upgrading to a server that runs PHP v5.6. Alas, that is not yet an option with GoDaddy since they never rush into upgrades until the latest version has been thoroughly tested.
Here’s that discussion: https://stackoverflow.com/questions/1912029/warning-cannot-modify-header-information-headers-already-sent-by-error
So I’m posting all this in the hope that Scott can check things on his end. On that same StackExchange post someone mentions that when the plugin PHP files are created, they need to be saved as “UTF-8 without BOM” (whatever that means). That solved someone elses problem with this same error, but he was modding Scott’s PHP.
How about it Scott? Any further insights on this issue? I like everything else about this plugin, and I checked several other plugins for digital media sales. This one was the easiest to configure and use. Now I just want to start selling digital media. Thanks!
